Does the fuel tank size have any impact on fuel economy between vehicles?

For example the new Honda Accords have a 56 Litre tank while the CRV has a 53 L and the Rogue a 55 L.

Now the 2 latters are compact crossovers and are arguably bigger in size than the Accord, so would that mean they are using up more gas? Would that mean its better to buy the Accord if we were going based on just gas mileage?

The fuel tank size of any vehicle is a compromise between the space available to fit it and the expected range of the vehicle.
It has little to do with fuel economy.

No direct correlation, as the car with the larger tank may get the same mileage, and just have a longer range.
There's a weight penalty for carrying more fuel, but 2 or 3 liters difference would be negligible.

It is completely irrelevant on the MPG. Only on the maximum distance between fillups.

It has absolutely nothing whatsoever to do with the fuel mileage of the vehicle.

The size of the tank has ZERO effect on fuel economy. On the other hand, fuel economy is on factor used to determine what size tank the manufacturer puts in the vehicle. Vehicles with lower miles per gallon tend to have larger tanks.

Just as much as taking out your fat friends to lunch. However, the car gets a little lighter as the fuel gets used up. The friends get heavier after lunch.